Safety attachment for punch presses



July 5, 1.932. B. J. VICTOR 1,865,806

SAFETY ATTACHMENT FOR PUNCH PRESSES Filed Dec. 5, 1950 2 Sheets-Sheet lJuly 5, 1932. B. J. VICTOR SAFETY ATTACHMENT FOR PUNCH PRESSES PatentedJuly 5, 1932 V UNITED STATES PATENT oFFicE BENJAMIN J'. VICTOR, OF OAKPARK, ILLINOIS, ASSIGNOR TO VICTOR MANUFACTUR- ING 80 GASKET COMPANY, OFCHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS SAFETY ATTACHMENT FOR PUNCHPRESSES l' Application filed December This invention relates to safetyattachments for punch presses and the like and the object broadly is topositively prevent the machine from being operated until both hands ofthe operator are employed to set the machine in operation.

Another object of the invention is to insure against accidental failureof the safety attachment of a punch press or other machine by positivelylocking the machine against operation and holding it in this lockedposition until both hands of the operator are used to set the machine inoperation.

Further objects of the invention are to provide locking devices movablefrom looking position but constantly urged into look ing position; toprovide locking devices c0nstantly urged into locking position byyieldable members located in plain View of the op- 9 erator sothat hewill be readily apprized of breakage thereof; to provide supports forthe yieldable members urging the locking dogs into locking position soas to prevent displacement of said yieldable members; to

provide locking members which will be held from locking position aftermovement thereof therefrom until a cycle of operation of the machine hasbeen completed; and to provide locking members that may be connected byflexible members to the operating devices of the machine.

In the selected embodiment of the invention illustrated in theaccompanying drawings Fig. l is a fragmentary front elevation of a punchpress with which my invention has been associated;

Fig. 1a is a perspective detail viewof a portion of the device; Fig. 2is a vertical sectional view taken substantially on the line 22 on Fig.1;

Fig. 3 is a fragmentary elevational detail view of the locking members,said members being shown in the completely unlocked position thereof inthe cycle of operation;

Fig. 1 is a fragmentary plan view of the parts as illustrated in Fig. 3;and

Fig. 5 is a fragmentary sectional detail view.

The invention disclosed in the accompany- 5, 1930. Serial No. 500,220.

ing drawings is an improvement over that described and claimed in myPatent No. 1,783,817 for punch press safety devices, patented December2, 1930. In the drawings wherein I have illustrated a selectedembodiment of this invention I have shown apunch press embodying a frame5 having a crank shaft 6 journaled therein to which a ram 7 is connectedto be movable thereby toward and away from the bed 8. The ram 7 and thebed 8 carry dies 9 for punching or otherwise operating on materialintroduced therebetween when the ram 7 moves toward the bed 8. The crankshaft 6 is operated by a pulley flywheel 10 rotatably mounted on theshaft and which may be operatively secured thereto, as required, by asuitable onerevolution clutch. The clutch shown in the drawingscomprises a clutch member 11 fast on the crank shaft 6 and provided witha spring-pressed clutch bolt 12 engageable in a recess in the hub of thewheel 10. The machine thus far described is a commercial punch press andit has been provided with an attachment for protecting the operatoragainst injury in the operation of the press that requires both hands ofthe operator to set the machinein operation. This attachment includes ashaft 13 journaled in and extended across the frame. On one end of thisshaft an operating lever 14 is fixed that includes a handle 15. On theother end of the shaft an operating lever 16 is pivotally mounted andthis lever includes a handle 17. On the side of the frame 5 a bracket 18is mounted on which the lever arm 24 is pivotally mounted. The lever arm24. includes a projecting arm 25 normally arranged above the arm 26 onthe bracket 18 and a pin 27 is extended through aligned openings in thearms 25 and 26. A spring 28 is disposed about the pin 27 between thehead 29 thereof and the arm 25 and urges the arm into engagement withthe projecting arm 26 and also urges the head 30 of the pin intoengagement with the opposite side of the arm 26. On the lever arm 24 abalance lever 31 is medially mounted. A link 32 interconnects one end ofthe lever 31 to the operating lever 16. A link'33 interconnects theother end of the balance lever 31 and the arm 34 fixed on the shaft 13.The lever arm 24 is connected by a rod 35 with the spring pressed clutchthrowout lever 36 that normally holds the clutch bolt 12 in disengagedposition. lVhen both the handles 15 and 17 are gripped and moveddownwardly simultaneously, movement is transmitted through the links 32and 33 to both ends of the balance lever 31, and the lever arm 24 ispivoted downwardly against the action of the spring 28 and this movementis transmitted through the rod 35 to the clutch throwout lever 36 whichis thus retracted from the position shown in Fig. 2 to permit the clutchbolt 12 to move into engaging position to interconnect the wheel 10 tothe shaft 6 and cause operation of the machine. If only the handle 15 ismoved the shaft 13 will be motivated and movement will be transmittedthrough the link 33 and therefore the balance lever 31 will merely pivoton the lever arm 24 and likewise if only the handle 17 is moved movementwill be transmitted through the link 32 to again merely pivot thebalance lever 31 about its pivotal mounting without imparting movementto the lever arm 24. It is therefore manifest that conjoint movement ofthe handles 15 and 17 is necessary to bring about operation of themachine. However, the clutch controlling the connection between theflywheel 10 and the shaft 6 may, under certain conditions, fail todisengage or, for another similar cause, another operation of themachine may result. Such additional operation without an interveningoperation of the handles 15 and 17 is known as a repeat operation. Theoperator of the machine e2;- pecting that the same will stop after oneoperation thereof will reach in between the dies 9 to remove thematerial that has been operated on and if the machine makes a repeatoperation it is possible that his hands will be caught between the diesand be crushed thereby. It is the object of my invention to providelocking means independent of and separate from the power means of themachine for positively and solidly locking the ram so that it cannotoperate un less and until the operator by the use of both hands operatesthe levers 14 and 16. To this end a cross bar 37 is secured to theconnecting rods of the ram. Substantially L- shaped brackets 37 areattached to the con necting rods by the cap screws 6 that secure saidconnecting rods to the cranks on the shaft 6. The ends of these bracketsrest on the upper edge of the cross bar to reenforce the mountingthereof and to further reenforce this mounting dowel pins are passedthrough the cross bar into the connecting rods. The L-shaped bracketsand the dowels aid in dissipating the shearing stress exerted on thebolts securing the cross bar in position when thecross bar acts tointerrupt a repeat operation. On the front face of the guides 38, 38 onthe frame 5 for the ram 7 I mount blocks 39, 39 having bifurcations 40,40 in the upper ends thereof extended transversely of the machine.Shafts 41, 41 are extended through these bifurcations and fixed thereonwith portions thereof extended into the bifurcations are looking dogs42, 42 having shoulders .43, 43 thereon which engage opposite ends ofthe cross bar 37 when the machine is in at rest position. The engagementof the shoulders 43, 43 with the cross bar 37 prevents downward movementof the ram 7 until the locking dogs 42, 42 have been moved fromretaining position, shown in Fig. 1. On the forward ends of the shafts41, 41 are pins 44, 44 having heads thereon through which the arcuateguides 45, 45 are extended, said guides being supported on brackets 46,46 on the blocks 39, 39. Disposed about the guides 45, 45 are springs47, 47 which act on the pins 44, 44 and consequently the shafts 41, 41to urge the locking dogs carried by said shafts into retaining position,this action being limited by the fingers 48, 48 on the locking dogs thatengage opposite ends of the cross bar 37. It is therefore manifest thatthe locking dogs are constantly urged into retaining position. Moreover,the springs which urge these looking dogs into retaining position aredisposed at the front of the machine in plain view of the operator. Thusbreakage of these springs may be ascertained easily by the operator.Moreover, the springs are mountedon guides which support the same andtherefore even if either of the springs should break in a plurality ofplaces some effect thereof will remain since displacement will beprevented and therefore the locking dogs will be urged into lockingposition. Since the locking dogs act on the cross bar when the machineis in at rest position it is necessary that the locking dogs be movedfrom retaining position before the machine can be operated. In order toaccomplish this, chains 49, 49 are respectively connected to the levers14 and 16 and to the sides of adjacent of the locking dogs 42.Therefore, when the levers are moved downwardly, as above described,this movement will be transmitted through the chains to the locking dogsto pivot them from retaining position. It is desirable that the operatorbe required to keep his hands on the handles 15 and 17 for a suiiicientperiod of time to permit the dies to move into close relationship witheach other, for this will obviate the likelihood of the operatorcarelessly placing his hands between the dies during the downward strokeof the ram. Moreover, it is necessary that the locking dogs be held fromretaining position until and only until the parts have moved back intoat rest position. To accomplish these ends slide bars 50, 50 are mountedin grooves in opposite ends of the cross bar 37. These slide bars areretained in position by U shaped brackets 50 fitted over the ends of thecross bar and secured thereto. The slide bars include projections 51, 51having openings therein through which corresponding ends of links 52, 52may be extended, these links having heads 53, 53 thereon that areadapted to engage the projections 51, 51 when the links 52, 52 are moveddownwardly.

Corresponding ends of the links 52, 52 are respectively pivotallyconnected to the locking dogs 42, 42 at 54, 54. Therefore, when thelocking dogs 42, 42 are pivoted from retaining position, as illustratedin Fig. 1, into the position illustrated in Fig. 3 wherein the dogs areentirely out of locking position. Movement will be transmitted throughthe links 52, 52 to move the slide bars 50, 50 downwardly and the lowerends of the slide bars will project below the lower edge of the crossbar 37 as illustrated in Fig. 3. Therefore when the operator removes hishands from the handles 15 and 17 the springs 47 47 will act to pivot thelocking dogs back into locking position but the locking dogs will engagethe projecting portions of the slides 50, 50 and will be held frommovement into locking position during the downward movement of the ram.As soon as the ram starts to move up, the cross bar and the slide barswill move therewith and the slide bars will engage the shoulders 55, 55on the locking dogs 42, 42 and will be held against movement and as thecross bar continues to move with the ram there will be a relativemovement between the slide bars and the cross bar and the slide barswill be repositioned, as shown in Fig. 1, upward movement of the slidebars being limited by engagement thereof with the stops 51, 51 carriedby the cross bar. When the cross bar 37 moves upwardly with the ramthese slide bars will move therewith. In order to insure upward movementof the slide bars 50, 50 with the cross bar 37, an arrangement such asthat shown in Fig. 5 is provided. By referring thereto it may be seenthat an opening 56 extends inwardly from the end of the cross bar 37 andthat a spring 57 is confined therein which acts on a ball 58. The ball58 therefore is urged toward the slide bar 50 which has spaced sockets60 therein. When the slide bar is positioned as shown in Fig. 1, theball 58 is urged into the lowermost of the sockets 60 and therefore theslide bar is releasably connected to the cross bar. When the slide baris moved downwardly into the position illustrated in Fig. 3 the ball 58is seated in one of the other sockets 60 and the slide bar is againconnected to the cross bar 37. An arrangement such as this is providedfor both of the slide bars and therefore proper movement thereof withthe cross bar is assured. There is sufficient clearance between theheads 53 and the projections 51 to insure that the operator will movethe handles 15 and 17 downwardly in an appreciable amount before theslide bars will move into position to withhold the locking dogs andtherefore premature or careless operation is prevented. The levers 14and 16 are repositioned through the chains 49, 49 by the action of thesprings 47, 47 on the locking dogs 42, 42. The controlling chains 49, 49are properly fitted and adjusted to insure that the machine Will not betripped until the dogs 42, 42 are clear of the cross bar 37 The dogs arepivoted and counter-balanced by the springs 45, 45 and may be operatedwith minimum effort.

It is manifest from the foregoing description that I have provided asafety attachment which will effectively prevent a repeat operation of apunch press. This device is so arranged that conjoint operation oflevers by the use of both of the operators hands is required.Furthermore, the locking members are effectively urged into lockingposition by devices effectively prevented from into locking position tothereby obviate any repeat operation of the machine.

In the foregoing description I have set forth a selected embodiment ofmy invention as used on a punch press but it is to be understood thatthis device might be used on other machines and that variations andmodifications may be made therein and I therefore do not wish to belimited to the precise details set forth but desire to avail myself ofsuch changes and alterations as fall within the purview of the followingclaims.

I claim: r

1. In a machine of the character described, the combination of a frame,a ram and meansfor operating the same, means for stopping the ram at theend of a cycle of operation, a cross bar carried by the ram, lockingdogs pivotally mounted on the frame and normally disposed in stoppingposition in engagement with opposite ends of the cross bar, yieldablemeans acting directly on said locking dogs for urging said locking dogsinto said stopping position, means for supporting said yieldable meansto prevent displacement thereof, and means including levers connectedwith the stopping means and the locking dogs and requiring conjointoperation for retracting said stopping means and said locking dogs topermit a cycle of operation of said machine.

2. In a machine of the character described, the combination of a frame,a ram and means for operating the same, means for stopping the ram atthe end of a cycle of operation, a cross bar carried by the ram, lockingdogs pivotally mounted on the frame and normally disposed in stoppingposition in engagement with opposite ends of the cross bar, yieldablemeans acting directly on said locking dogs for urging said locking dogsinto said stopping position, means for supporting said yieldable meansto prevent displacement thereof, means including levers requiringconjoint operation for retracting said stopping means and said lockingdogs to permit a cycle of operation of said machine, and means forholding said locking dogs out of stopping position during the cycle ofoperation of the machine.

3. In a machine of the character described, the combination of a. frame,a ram and means for operating th same, means for stopping the ram at theend of a cycle of operation, :a cross bar carried by the ram, slide barsat opposite ends of the cross bar, locking dogs pivotally mounted on theframe and normally disposed in stopping position in engagement withopposite ends of the cross bar, yieldable means for urging said lockingdogs into said stopping position, means for supporting said yieldablemeans to prevent dis placement thereof, means including levers requiringconjoint operation for retracting said stopping means and said lockingdogs to permit a cycle of operation of said machine, and means forconnecting said slide bars to said locking dogs whereby. said slide barswill be moved into position to withhold said locking dogs from stoppingposition during a cycle of operation of the machine.

4c. In a punch press which has a frame, a ram, means for operating theram, and means for controlling the operating means, the combination of asafety means including a cross bar movable with the ram, locking dogspivotally mounted on the frame and engaging the cross bar at the endsthereof to prevent downward movement of the ram, yieldable means actingdirectly on said looking dogs for urging said locking dogs intoengagement with the cross bar, means for supporting said yieldable meansto prevent displacement thereof, means for withdrawing the locking dogsfrom engagement with the cross bar when the controlling means are operated, and chains interconnecting said looking dogs and saidwithdrawing means.

5. In a punch which has a frame, a ram, means for operating the ram, andmeans for controlling the operating means, the combination of a safetymeans including a cross bar movable with the ram, locking dogs pivotally mounted on the frame and having shoulders thereon engageable withthe cross bar at the end thereof to prevent downward movement of theram, means for withdrawi the locking dogs from engagement with erated,and means at opposite ends of the cross bar for withholding theshoulders on the locking dogs from engagement with the bar afterwithdrawal thereof by said with drawing means.

6. In a punch press which has a frame, a ram, means for operating theram, and means for controlling the operating means, the combination ofasafety means including a cross bar movable with the ram, locking dogspivotally mounted on the frame and having shoulders thereon engageablewith the cross bar at the end thereof to prevent downward movement ofthe ram, means for withdrawing the locking dogs from engagement with thebar when the controlling means are operated, and means at opposite endsof the cross bar and movable from the locking dogs to withhold theshoulders on said dogs from engagement with said bar after withdrawalthereof by said withdrawing means.

7. In a punch press which has a frame, a ram, means for operating theram, and means for controlling the operating means, the combination of asafety means including a cross bar movable with the ram, locking dogspivotally mounted on the frame and having shoulders thereon engageablewith the cross bar at the end thereof to prevent downward movement ofthe ram, means for withdrawing the locking dogs from engagement with thebar when the controlling means are operated, means at opposite ends ofthe cross bar for withholding the shoulders on the locking dogs fromengagement with the bar after withdrawal thereof by said withdrawingmeans, and means for releasably retaining the means at opposite ends ofthe cross bar in determined positions.

8. In a punch press which has a frame, a ram, means for operating theram, and means for controlling the operating means, the combination of asafety means including a cross bar movable with the ram, locking dogspivotally mounted on the frame and engaging the cross bar at the endsthereof to prevent downward movement of the ram, yieldable means forurging said locking dogs into engagement with the ram, means forwithdrawing the locking dogs from engagement with the bar when thecontrolling means are operated, slide bars mounted at opposite ends ofthe cross bar, and links for interconnecting said locking dogs and saidslide bars whereby said slide bars will be moved when said looking dogsare withdrawn by said withdrawing means, said slide bars engaging saidlocking dogs to withhold the same from engagement with the cross barduring movement thereof with the ram.

9. In a punch press which has a frame, a ram, means for operating theram, and means for controlling the operating means, the combination of asafety means including a cross bar movable with the ram, locking dogspivotally mounted on the frame and engaging the cross bar at the endsthereof to prevent downward movement of the ram, yieldable means forurging said locking dogs into engagement with the ram, means forwithdrawing the locking dogs from engagement with the bar when thecontrolling means are 0perated, slide bars mounted at opposite ends ofthe cross bar links for interconnecting said locking dogs and said slidebars whereby said slide bars will be moved when said locking dogs arewithdrawn by said withdrawing means, said slide bars engaging saidlocking dogs to withhold the same from engagemen with the cross barduring movement thereof with the ram, and means for releasably retainingsaid slide bars in determined positions relative to said cross bar.

BENJAMIN J. VICTOR.

